1. Field of the Invention
The present invention relates to belts for a continuously variable transmission comprising metal rings formed as endless bands and a large number of metal elements supported along the metal rings, the belts transmitting drive power by being wrapped around a drive pulley and a driven pulley.
2. Description of the Prior Art
Since the durability of such belts for a continuously variable transmission is determined primarily by the durability of the metal rings, attempts have been made to enhance the durability by increasing the lateral width of the metal rings thereby decreasing the tensile stress.
Furthermore, Japanese Patent Publication No. 5-48364 describes a case where the metal rings are prevented from moving towards the neck parts of the metal elements by setting the circumference of the metal ring which is in contact with the saddle surfaces of the metal elements, which have been subjected to crowning, so that it is short at the lateral outer side and long at the lateral inner side.
When there is misalignment between the drive pulley and the driven pulley accompanying a change in the gear ratio of the continuously variable transmission, the metal rings move in a lateral direction inside the ring slots of the metal elements. Therefore, if the lateral width of the metal rings is increased in an attempt to enhance the durability thereof, a problem is caused in that the lateral edges of the metal rings come into contact with the neck parts of the metal elements or the V-faces of the pulleys and are worn. Moreover, there is a problem that due to the increase in the lateral width of the metal rings the lateral inner edge of the metal rings overhangs the saddle surfaces of the metal elements by a large amount when there is a misalignment, and thus flexural stress is applied to the metal rings thereby reducing their durability.
Furthermore, the case described in the above-mentioned publication has the problem that when the drive pulley and the driven pulley are misaligned, it is difficult to prevent the metal rings from coming into contact with the neck parts of the metal elements or the V-faces of the pulleys with certainty and no consideration is given to assuring the maximum power transmission capacity of the metal belt.